Redeveloping brownfield sites into attractive residential and commercial communities is a priority for local councils who have housing targets to meet. Bhushan Kumar, Business Development Manager at Eclipse Power Networks describes the IDNO’s involvement in energising a brownfield redevelopment at Smiths Farm, Northolt.
The argument for building on brownfield land is strong. It delivers significant environmental, social and cost advantages to local communities. While it looks and sounds like a winner on paper, the practicalities involved in getting planning permission and the costs associated with remediation, infrastructure and biodiversity net gain (BNG) can be a deterrent.
One particular 1.5-hectare site at Smiths Farm lying within the Metropolitan Green Belt had been used for commercial purposes for the last 30 years. Considered a local eyesore, the unprepossessing brownfield site was ripe for redevelopment to provide housing and residential amenities. The area has an acute housing need, especially for affordable homes. Redevelopment of the site had been on the cards for over a decade, with several planning hurdles to overcome.
The mixed-use re-development of the brownfield site within the green belt faced considerable challenges and the application went through several iterations before planning permission was granted by Ealing Council. The plans needed to accommodate the sympathetic development of a listed farmhouse and barns, and environmental considerations such as sustainable drainage systems and boosting biodiversity and amenity value.
An all-electric site
Ealing Borough Council approved the project to replace the existing commercial and storage units with 220 residential apartments, 50% of which are affordable, a café and assorted commercial and industrial units.
A key requirement for the development’s planning consent was that it met the “Lean, Clean, Green” energy hierarchy required by London Plan policies SI2 and SI3, and Ealing Council’s own Development Management DPD. This meant a significant reduction in carbon dioxide emissions. As there was no gas infrastructure on site, combined heat and power (CHP) was not an option. There was also no nearby “Clean” district heat network (DHN). As all heating and hot water would need to be powered by electricity.
Heat pumps were a natural choice for both their efficiency and environmental benefits. When it comes to heating and/or cooling homes and workplaces, heat pumps are a highly efficient alternative to traditional boiler systems, producing typically three times more heating and cooling capacity than the amount of electrical energy they consume. The heat provided by the air and water sourced pumps is harvest from the environment rather than coming directly from a carbon dioxide emitting energy source like natural gas.
The proposals specified electric Air Source Heat Pump distribution loops (ASHP) for all 220 homes, and dwelling Water Source Heat Pumps (WSHP) to provide space heating and domestic hot water.
Together the Air and Water Source Heat Pumps installed at Smiths Farm will achieve a combined annual reduction of at least 79.23%, equal to 138.90 tonnes, in regulated carbon dioxide (CO2) emissions.
Further renewable energy will be supplied by five photo-voltaic arrays that will be installed on the roofs of the housing blocks, providing a combined capacity of around 115 kWp. In addition to the heat pumps, the redevelopment will also include electric vehicle (EV) charging points for residents and visitors to the shop, café and other amenities – adding to the size of the electrical connection required.
All in, the electrical requirements of the site were calculated to need a 1.5MVA high voltage (HV) connection to the grid within the SSE South region. The connection will supply the 14 MPANs required by the industrial and commercial units, two for the EV charge points and a further 220 residential MPANS.
Independence equals flexibility and enhanced value
The design and installation of the new 1.5 MVA high voltage connection and network to provide power will be delivered by an Independent Connections Provider (ICP). The adoption and ongoing operations and maintenance of the network will be managed by an Independent Distribution Network Operator (IDNO).
The comprehensive electricity network designed to provide power to the residents and commercial enterprises on this tricky site calls for flexibility, reliability and responsiveness to optimise the availability of power across the site for residents, business owners and customers.
ICPs and IDNOs give developers greater choice when it comes to designing, connecting and energising residential developments, and adopting those assets over the long-term. Working with an IDNO can provide a flexible and cost-effective engineering solution for projects as they can interpret the standards set by DNOs more flexibly than the DNO itself. IDNOs are regulated by Ofgem and are required to meet the same standards and obligations and a DNO. They take on the responsibility of adopting and managing networks as safely and intelligently as possible. However, they can provide alternative technical approaches that better suit the site, especially a complex redevelopment like Smiths Farm.